Discovery rates

I talked yesterday about the rate of discovery for dinosaurs and the almost overwhelming mass on new taxa that are constantly appearing. While this is inherently important, what’s more interesting is what this can (or rather cannot) tell us about the total number of dinosaur species that might be out there. In short, 175-ish years since dinosaurs first started being found and recognised as such there has been no real sign of discoveries slowing down and in fact the rate looks to be picking up. With new and important localities in Australia, Argentina and Asia looking very profitable, this might accelerate still further. Even allowing for synonymy we are obviously getting quite a lot of new dinosaurs right now.

In the past people have attempted to predict the total number of dinosaur species that might be out there to be recovered (and obviously that;s not the same as how many there were – not all of them would have entered the fossil record or be identifiable). However, this rather relies on knowing how the discovery rate is changing and also it might change in the future. The rate of discovery of species of all kinds (both living and fossil) follow pretty similar patterns (as shown here rather well on Tet Zoo). They start slow, then shift into an exponential phase and eventually as researchers get near the limit of species to be found, this tails off and flattens out as it takes more and more work to find fewer and fewer species.

The thing is, as long as you are in the exponential phase of discovery, it’s impossible to tell when then tail off is going to be hit. It could be in a couple of years, or it could continue for decades. For the moment, all we can say is that it’s still going up, fast, and with no tail off in sight, we can expect these kinds of discoveries to keep coming. It’ll be some time yet before we can start to think about knowing just how many dinosaurs are out there to add to our taxonomic list.